<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <img th:src="@{/image/500.png}" src="../../static/image/500.png" style="position: fixed; top: 50%; left: 50%; transform: translate(-50%,-50%);"/>
</body>
</html>